Conceptual structure: Older children (7-9y)
Our three methods for determining how many factors to retain all suggested retaining three factors.
As in Study 1, the conceptual structure revealed by this analysis among 7- to 9-year-old children was very similar to that of adults, again characterized by a three-way distinction between BODY, HEART, and MIND.
After rotation, the first factor corresponded primarily to physiological sensations. An analysis of factor congruence confirmed that this factor was most similar to adults’ BODY factor (cosine similarity with BODY: 0.97; with HEART: 0.65; with MIND: 0.63). It was the dominant factor for such items as feel pain, feel scared, get hungry, and smell things, and accounted for 39% of the shared variance in the rotated three-factor solution.
The second factor corresponded primarily to social-emotional abilities. An analysis of factor congruence confirmed that this factor was most similar to adults’ HEART factor (cosine similarity with HEART: 0.98; with BODY: 0.66; with MIND: 0.48). It was the dominant factor for such items as feel embarrassed, feel guilty, feel proud, and feel sad, and accounted for 35% of the shared variance in the rotated three-factor solution.
The third factor corresponded primarily to perceptual-cognitive abilities. An analysis of factor congruence confirmed that this factor was most similar to adults’ MIND factor (cosine similarity with MIND: 0.96; with HEART: 0.47; with BODY: 0.62). It was the dominant factor for such items as figure out how to do things, make choices, remember things, and sense temperatures, and accounted for 26% of the shared variance in the rotated three-factor solution. (See Figure 4, Panel C, for all factor loadings.)
We consider this to be a close conceptual replication of our Study 1 findings, suggesting that by the age of 7-9 years, this three-part conceptual structure is stable and robust to a range of experimental conditions.
Conceptual structure: Younger children (4-6y)
Our three methods for determining how many factors to retain each suggested retaining different numbers of factors: Weisman et al.’s factor retention criteria suggested retaining three factors, parallel analysis suggested retaining two factors, and minimizing BIC suggested a null, one-factor solution. Here we present both the two- and three-factor solutions. (See SOM for factor loadings on the one “factor” in the null, one-factor solution.)
Three-factor solution
In the rotated three-factor solution suggested by Weisman et al.‘s retention criteria, the first factor corresponded primarily to physiological sensations, as well as some positive emotions. An analysis of factor congruence indicated that this factor was most similar to adults’ BODY factor (cosine similarity with BODY: 0.92), but was also quite similar to adults’ HEART factor (cosine similarity with HEART: 0.81; with MIND: 0.7). It was the dominant factor for such items as feel tired, get angry, get hungry, and get hurt feelings, and accounted for 40% of the shared variance in the rotated three-factor solution.
The second factor corresponded primarily to perceptual-cognitive abilities, as well as one complex negative emotion (feel guilty). An analysis of factor congruence confirmed that this factor was most similar to adults’ MIND factor (cosine similarity with MIND: 0.94; with HEART: 0.67; with BODY: 0.71). It was the dominant factor for such items as feel guilty, figure out how to do things, remember things, and sense temperatures, and accounted for 30% of the shared variance in the rotated three-factor solution.
The third factor corresponded primarily to social-emotional abilities, with particularly strong loadings for positive emotions. An analysis of factor congruence indicated that this factor was most similar to adults’ HEART factor (cosine similarity with HEART: 0.87), but also quite similar to adults’ BODY factor (cosine similarity with BODY: 0.81; with MIND: 0.62). It was the dominant factor for such items as feel happy, feel love, feel proud, and feel scared, and accounted for 30% of the shared variance in the rotated three-factor solution. (See Figure 4, Panel B, for all factor loadings.)
Two-factor solution
In the rotated two-factor solution suggested by parallel analysis, the first factor encompassed both physiological sensations and emotions. An analysis of factor congruence indicated that this factor was most similar to adults’ BODY factor (cosine similarity with BODY: 0.93), but was also quite similar to adults’ HEART factor (cosine similarity with HEART: 0.88; with MIND: 0.7). It was the dominant factor for such items as feel happy, feel sick, get angry, and get hungry, and accounted for 65% of the shared variance in the rotated two-factor solution.
The second factor corresponded primarily to perceptual-cognitive abilities. An analysis of factor congruence confirmed that this factor was most similar to adults’ MIND factor (cosine similarity with MIND: 0.94; with HEART: 0.73; with BODY: 0.73). It was the dominant factor for such items as feel guilty, remember things, sense temperatures, and sense whether something is close by or far away, and accounted for 35% of the shared variance in the rotated three-factor solution. (See Figure 4, Panel A, for all factor loadings.)

Attributions of mental life
In Study 1, we saw that even children as old as 7-9y—whose conceptual structure seemed to be quite similar to that of adults’—nonetheless differed from adults in their application of this concept, attributing far more of the social-emotional abilities related to the HEART to both beetles and robots. How do children’s mental capacity attributions compare to adults for the larger set of target characters included in Study 2—and what does this aspect of conceptual developmental look like earlier in development (4-6y)?
Following Study 1, we approached these questions from several angles.
First, we projected all of children’s responses into the factor space defined by adults (standardized in terms of adults’ responses), and examined factor scores by age group (again, using the method articulated by ten Berge et al., 1999). As in Study 1, this yielded three scores for each participant, corresponding, in principle, to holistic judgments of the social-emotional, physiological, and perceptual-cognitive abilities of the target character the participant evaluated. (Note that each of these three scores takes into account adult factor loadings for all 20 mental capacities, as shown in Figure 4, Panel D.)
This allowed us to examine the effects of age group (younger children, older children, adults), character (computer, robot, doll, teddy bear, beetle, bird, mouse, goat, elephant), and factor (BODY, HEART, MIND) on these scores via mixed effects Bayesian regression. As in Study 1, age group and factor were treated as categorical variables and effect-coded. To explore attributions to different target characters, we included eight orthogonal contrasts: (1) animates (elephant, goat, mouse, bird, beetle) vs. inanimates (teddy bear, doll, robot, teddy bear); (2) mammals (elephant, goat, mouse) vs. other animals (bird, beetle); (3) elephant vs. other mammals (goat, mouse); (4) goat vs. mouse; (5) bird vs. beetle; (6) technologies (robot, computer) vs. toys (teddy bear, doll); (7) robot vs. computer; and (8) teddy bear vs. doll. Here we will focus on what we consider to be the two contrasts of the greatest theoretical interest: animates/inanimates (contrast #1) and, within inanimates, technologies/toys (contrast #6). (See SOM for a deeper investigation of the other six contrasts.)
The results of a maximal model can be found in Table 3; Figure 5 for scores by age group, factor, and character; and Figure 6 for scores by age (among children).
Table 3: Fixed effects from a mixed-effects Bayesian regression model predicting factor scores in Study 2 by character, factor (BODY, HEART, MIND), and age group. The model used the formula 'factor score ~ factor * age group * character + (1 | subject)' and was implemented in the 'brms' package for R (Bürkner, 2017). Factor and age group were effect-coded; character was coded with orthogonal contrasts (see main text). Asterisks mark parameters whose 95% credible interval does not include 0.
| Parameter |
b |
Error |
95% CI |
|
| (Intercept) |
0.02 |
0.02 |
[-0.02, 0.07] |
|
| characters: animates vs. inanimates |
0.08 |
0.01 |
[ 0.06, 0.09] |
* |
| characters: mammals vs. other animals |
0.02 |
0.01 |
[-0.01, 0.05] |
|
| characters: elephant vs. other mammals |
0.03 |
0.03 |
[-0.03, 0.09] |
|
| characters: goat vs. mouse |
0.02 |
0.05 |
[-0.08, 0.13] |
|
| characters: bird vs. beetle |
0.08 |
0.05 |
[-0.03, 0.18] |
|
| characters: technologies vs. toys |
0.10 |
0.04 |
[ 0.02, 0.18] |
* |
| characters: robot vs. computer |
0.13 |
0.05 |
[ 0.02, 0.23] |
* |
| characters: teddy bear vs. doll |
0.07 |
0.06 |
[-0.05, 0.18] |
|
| HEART (vs. grand mean) |
0.44 |
0.03 |
[ 0.38, 0.51] |
* |
| MIND (vs. grand mean) |
-0.47 |
0.04 |
[-0.54, -0.40] |
* |
| age group (4-6y vs. grand mean) |
-0.01 |
0.03 |
[-0.08, 0.06] |
|
| age group (7-9y vs. grand mean) |
0.08 |
0.03 |
[ 0.01, 0.14] |
* |
| characters (animates/inanimates) × HEART |
-0.04 |
0.01 |
[-0.05, -0.02] |
* |
| characters (mammals/other animals) × HEART |
0.03 |
0.02 |
[ 0.00, 0.07] |
|
| characters (elephant/other mammals) × HEART |
0.12 |
0.04 |
[ 0.05, 0.20] |
* |
| characters (goat/mouse) × HEART |
0.13 |
0.07 |
[-0.01, 0.27] |
|
| characters (bird/beetle) × HEART |
0.15 |
0.07 |
[ 0.01, 0.29] |
* |
| characters (technologies/toys) × HEART |
-0.10 |
0.05 |
[-0.20, 0.00] |
|
| characters (robot/computer) × HEART |
0.17 |
0.08 |
[ 0.02, 0.32] |
* |
| characters (teddy bear/doll) × HEART |
0.05 |
0.08 |
[-0.10, 0.21] |
|
| characters (animates/inanimates) × MIND |
-0.05 |
0.01 |
[-0.06, -0.03] |
* |
| characters (mammals/other animals) × MIND |
-0.04 |
0.02 |
[-0.08, -0.01] |
* |
| characters (elephant/other mammals) × MIND |
-0.02 |
0.04 |
[-0.10, 0.06] |
|
| characters (goat/mouse) × MIND |
-0.05 |
0.07 |
[-0.19, 0.10] |
|
| characters (bird/beetle) × MIND |
-0.12 |
0.07 |
[-0.27, 0.02] |
|
| characters (technologies/toys) × MIND |
0.49 |
0.05 |
[ 0.39, 0.59] |
* |
| characters (robot/computer) × MIND |
-0.03 |
0.07 |
[-0.17, 0.12] |
|
| characters (teddy bear/doll) × MIND |
-0.06 |
0.08 |
[-0.22, 0.10] |
|
| characters (animates/inanimates) × age group (4-6y vs. GM) |
-0.02 |
0.01 |
[-0.04, -0.01] |
* |
| characters (mammals/other animals) × age group (4-6y vs. GM) |
-0.01 |
0.02 |
[-0.05, 0.03] |
|
| characters (elephant/other mammals) × age group (4-6y vs. GM) |
-0.03 |
0.04 |
[-0.11, 0.05] |
|
| characters (goat/mouse) × age group (4-6y vs. GM) |
0.04 |
0.07 |
[-0.10, 0.18] |
|
| characters (bird/beetle) × age group (4-6y vs. GM) |
-0.11 |
0.07 |
[-0.26, 0.04] |
|
| characters (technologies/toys) × age group (4-6y vs. GM) |
-0.09 |
0.05 |
[-0.20, 0.01] |
|
| characters (robot/computer) × age group (4-6y vs. GM) |
-0.08 |
0.08 |
[-0.23, 0.07] |
|
| characters (teddy bear/doll) × age group (4-6y vs. GM) |
-0.05 |
0.08 |
[-0.20, 0.11] |
|
| characters (animates/inanimates) × age group (7-9y vs. GM) |
-0.01 |
0.01 |
[-0.02, 0.01] |
|
| characters (mammals/other animals) × age group (7-9y vs. GM) |
0.01 |
0.02 |
[-0.02, 0.05] |
|
| characters (elephant/other mammals) × age group (7-9y vs. GM) |
-0.05 |
0.04 |
[-0.12, 0.03] |
|
| characters (goat/mouse) × age group (7-9y vs. GM) |
-0.07 |
0.07 |
[-0.21, 0.07] |
|
| characters (bird/beetle) × age group (7-9y vs. GM) |
-0.04 |
0.07 |
[-0.18, 0.09] |
|
| characters (technologies/toys) × age group (7-9y vs. GM) |
0.07 |
0.06 |
[-0.04, 0.18] |
|
| characters (robot/computer) × age group (7-9y vs. GM) |
0.14 |
0.08 |
[-0.01, 0.29] |
|
| characters (teddy bear/doll) × age group (7-9y vs. GM) |
0.04 |
0.08 |
[-0.12, 0.20] |
|
| HEART × age group (4-6y vs. GM) |
0.37 |
0.05 |
[ 0.27, 0.47] |
* |
| MIND × age group (4-6y vs. GM) |
-0.38 |
0.05 |
[-0.48, -0.29] |
* |
| HEART × age group (7-9y vs. GM) |
0.07 |
0.05 |
[-0.02, 0.17] |
|
| MIND × age group (7-9y vs. GM) |
-0.02 |
0.05 |
[-0.12, 0.08] |
|
| characters (animates/inanimates) × HEART × age group (4-6y vs. GM) |
0.04 |
0.01 |
[ 0.02, 0.06] |
* |
| characters (mammals/other animals) × HEART × age group (4-6y vs. GM) |
-0.01 |
0.03 |
[-0.07, 0.04] |
|
| characters (elephant/other mammals) × HEART × age group (4-6y vs. GM) |
-0.15 |
0.06 |
[-0.27, -0.04] |
* |
| characters (goat/mouse) × HEART × age group (4-6y vs. GM) |
-0.15 |
0.10 |
[-0.34, 0.05] |
|
| characters (bird/beetle) × HEART × age group (4-6y vs. GM) |
-0.36 |
0.10 |
[-0.56, -0.16] |
* |
| characters (technologies/toys) × HEART × age group (4-6y vs. GM) |
0.16 |
0.07 |
[ 0.01, 0.31] |
* |
| characters (robot/computer) × HEART × age group (4-6y vs. GM) |
0.05 |
0.11 |
[-0.16, 0.25] |
|
| characters (teddy bear/doll) × HEART × age group (4-6y vs. GM) |
-0.22 |
0.11 |
[-0.43, -0.01] |
* |
| characters (animates/inanimates) × MIND × age group (4-6y vs. GM) |
-0.01 |
0.01 |
[-0.03, 0.01] |
|
| characters (mammals/other animals) × MIND × age group (4-6y vs. GM) |
-0.04 |
0.03 |
[-0.09, 0.01] |
|
| characters (elephant/other mammals) × MIND × age group (4-6y vs. GM) |
0.15 |
0.06 |
[ 0.03, 0.26] |
* |
| characters (goat/mouse) × MIND × age group (4-6y vs. GM) |
0.18 |
0.10 |
[-0.01, 0.39] |
|
| characters (bird/beetle) × MIND × age group (4-6y vs. GM) |
0.08 |
0.10 |
[-0.12, 0.29] |
|
| characters (technologies/toys) × MIND × age group (4-6y vs. GM) |
-0.45 |
0.08 |
[-0.59, -0.30] |
* |
| characters (robot/computer) × MIND × age group (4-6y vs. GM) |
-0.43 |
0.10 |
[-0.63, -0.24] |
* |
| characters (teddy bear/doll) × MIND × age group (4-6y vs. GM) |
0.24 |
0.11 |
[ 0.03, 0.45] |
* |
| characters (animates/inanimates) × HEART × age group (7-9y vs. GM) |
0.00 |
0.01 |
[-0.02, 0.02] |
|
| characters (mammals/other animals) × HEART × age group (7-9y vs. GM) |
0.05 |
0.03 |
[ 0.00, 0.10] |
|
| characters (elephant/other mammals) × HEART × age group (7-9y vs. GM) |
-0.06 |
0.06 |
[-0.17, 0.04] |
|
| characters (goat/mouse) × HEART × age group (7-9y vs. GM) |
-0.12 |
0.10 |
[-0.33, 0.08] |
|
| characters (bird/beetle) × HEART × age group (7-9y vs. GM) |
0.09 |
0.10 |
[-0.10, 0.28] |
|
| characters (technologies/toys) × HEART × age group (7-9y vs. GM) |
0.03 |
0.08 |
[-0.12, 0.18] |
|
| characters (robot/computer) × HEART × age group (7-9y vs. GM) |
0.28 |
0.11 |
[ 0.07, 0.49] |
* |
| characters (teddy bear/doll) × HEART × age group (7-9y vs. GM) |
0.17 |
0.11 |
[-0.05, 0.39] |
|
| characters (animates/inanimates) × MIND × age group (7-9y vs. GM) |
-0.04 |
0.01 |
[-0.06, -0.01] |
* |
| characters (mammals/other animals) × MIND × age group (7-9y vs. GM) |
0.01 |
0.03 |
[-0.04, 0.06] |
|
| characters (elephant/other mammals) × MIND × age group (7-9y vs. GM) |
-0.04 |
0.05 |
[-0.14, 0.07] |
|
| characters (goat/mouse) × MIND × age group (7-9y vs. GM) |
-0.01 |
0.10 |
[-0.20, 0.20] |
|
| characters (bird/beetle) × MIND × age group (7-9y vs. GM) |
-0.14 |
0.10 |
[-0.33, 0.06] |
|
| characters (technologies/toys) × MIND × age group (7-9y vs. GM) |
0.17 |
0.08 |
[ 0.02, 0.32] |
* |
| characters (robot/computer) × MIND × age group (7-9y vs. GM) |
-0.10 |
0.11 |
[-0.31, 0.10] |
|
| characters (teddy bear/doll) × MIND × age group (7-9y vs. GM) |
-0.21 |
0.12 |
[-0.44, 0.01] |
|
First, we consider the contrast between the five animate target characters (beetle, bird, mouse, goat, and elephant) and the four inanimate target characters (computer, robot, doll, and teddy bear). BRIEF MENTION OF RELEVANT LITERATURE
As we would expect, collapsing across age groups and factors, factor scores suggest that participants generally attributed more mental capacities to animates than to inanimates (b = 0.08, 95% credible interval: [0.06, 0.09]). Relative to the grand mean, however, the difference between animates and inanimates was diminished in both the HEART domain (b = -0.04, 95% credible interval: [-0.05, -0.02]) and the MIND domain (b = -0.05, 95% credible interval: [-0.06, -0.03])—suggesting that this overall difference between animates and inanimates was driven primarily by attributions of the physiological sensations characteristic of BODY to biological animals (and not to inanimate objects).
In terms of developmental trends, the overall difference between animates and inanimates was somewhat attenuated among 4- to 6-year-old children (b = -0.02, 95% credible interval: [-0.04, -0.01])— but relatively less so in the HEART domain (b = 0.04, 95% credible interval: [0.02, 0.06]). Meanwhile, among 7- to 9-year-old children, the difference between animates and inanimates was attenuated in the MIND domain only (b = -0.04, 95% credible interval: [-0.06, -0.01]). Taken together, these findings suggest that, as a group, 4- to 6-year-old children perceived the difference between animates and inanimates to be a matter of both BODY and HEART (although they perceived this difference to be somewhat smaller than older children and adults). Meanwhile, as a group, 7- to 9-year-old children perceived the difference between animates and inaniamtes to be primarily a matter of the BODY, but the animate-inanimate distinction did not appear to govern their attributions of MIND. Neither of these patterns was entirely adult-like: Among adults, the distinction between animates and inanimates appeared to govern attributions of BODY and MIND to an equal degree, and HEART to a lesser extent. REWRITE FOR CLARITY, ADD OBSERVATIONS FROM PLOT
Next, we consider an important distinction within the group of inanimate target characters: the contrast between the two technologies (computer and robot) and the two anthropomorphic toys (doll and teddy bear). BRIEF MENTION OF RELEVANT LITERATURE
Collapsing across age groups and factors, participants generally attributed more mental capacities to technologies than to toys (b = 0.10, 95% credible interval: [0.02, 0.18]); as we might expect, this difference was exaggerated in the MIND domain (b = 0.49, 95% credible interval: [0.39, 0.59]).
In terms of developmental trends, the overall difference between technologies and toys did not differ across age groups (4-6y vs. the grand mean: b = -0.09, 95% credible interval: [-0.20, 0.01]; 7-9y vs. the grand mean: b = 0.07, 95% credible interval: [-0.04, 0.18])—but this several higher order effects (see Table 3). In particular, 4- to 6-year-old children were unique in their perceptions of the difference between technologies and toys in the MIND domain (b = -0.45, 95% credible interval: [-0.59, -0.30]): While older children and adults distinguished strongly between technolgoies and toys in their attributions of MIND, younger children generally attributed fewer of the perceptual-cognitive abilities of the MIND to either kind of inanimate being. CAN’T INTERPRET THE OTHER TWO SIGNIF 3-WAY INTERACTIONS
Taken together, these findings suggest that, as a group, 4- to 6-year-old children perceived the difference between animates and inanimates to be a matter of both BODY and HEART (although they perceived this difference to be somewhat smaller than older children and adults). Meanwhile, as a group, 7- to 9-year-old children perceived the difference between animates and inaniamtes to be primarily a matter of the BODY, but the animate-inanimate distinction did not appear to govern their attributions of MIND. Neither of these patterns was entirely adult-like: Among adults, the distinction between animates and inanimates appeared to govern attributions of BODY and MIND to an equal degree, and HEART to a lesser extent.


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A visual inspection of Figure 2 clarifies these findings. Attributions in the BODY and MIND domains were rather similar for children and adults: Both children and adults marked a clear difference between the robot and the beetle in the physiological sensations of the BODY (left), in line with the animate–inanimate distinction; and both age groups credited the robot with slightly greater perceptual-cognitive skills (MIND) than the beetle (right). In contrast, in the HEART domain (center) both the beetle and the robot received rather low scores among adults, but very high scores among children.
The raw data further supporst these observations; see Figure 3 for raw counts of no, kinda, and yes responses for all items, grouped by factor, character, and age group. For example, consider hunger (the first capacity under BODY): Across age groups, nearly every participant said that a beetle could get hungry, while few participants (with the exception of some children) said that a robot could. Likewise, for mathematical computations (the last capacity under MIND), virtually no participants said that a beetle was capable of doing math, while the vast majority of both adults and children said that a robot was. But for social-emotional abilities, like feeling proud, feeling joy, and feeling sad (the first three capacities under HEART), far more children than adults endorsed these capacities for beetles and robots. (See SOM for an analysis, parallel to the regression analyses here, of the proportion of the top-loading mental capacities for each factor that were endorsed by participants of different ages.)


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